scholarly journals She3p Possesses a Novel Activity Required for ASH1 mRNA Localization in Saccharomyces cerevisiae

2009 ◽  
Vol 8 (7) ◽  
pp. 1072-1083 ◽  
Author(s):  
Sharon M. Landers ◽  
Michelle R. Gallas ◽  
Jaime Little ◽  
Roy M. Long
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Rna Binding ◽  
Adaptor Protein ◽  
Mrna Localization ◽  
Rna Localization ◽  
The Novel ◽  
Specific Proteins ◽  
Type V ◽  
Localization Elements ◽  
Ash1 Mrna

ABSTRACT Intracellular and intercellular polarity requires that specific proteins be sorted to discreet locations within and between cells. One mechanism for sorting proteins is through RNA localization. In Saccharomyces cerevisiae, ASH1 mRNA localizes to the distal tip of the bud, resulting in the asymmetric sorting of the transcriptional repressor Ash1p. ASH1 mRNA localization requires four cis-acting localization elements and the trans-acting factors Myo4p, She3p, and She2p. Myo4p is a type V myosin motor that functions to directly transport ASH1 mRNA to the bud. She2p is an RNA-binding protein that directly interacts with the ASH1 mRNA cis-acting elements. Currently, the role for She3p in ASH1 mRNA localization is as an adaptor protein, since it can simultaneously associate with Myo4p and She2p. Here, we present data for two novel mutants of She3p, S348E and the double mutant S343E S361E, that are defective for ASH1 mRNA localization, and yet both of these mutants retain the ability to associate with Myo4p and She2p. These observations suggest that She3p possesses a novel activity required for ASH1 mRNA localization, and our data imply that this function is related to the ability of She3p to associate with ASH1 mRNA. Interestingly, we determined that She3p is phosphorylated, and global mass spectrometry approaches have determined that Ser 343, 348, and 361 are sites of phosphorylation, suggesting that the novel function for She3p could be negatively regulated by phosphorylation. The present study reveals that the current accepted model for ASH1 mRNA localization does not fully account for the function of She3p in ASH1 mRNA localization.

scholarly journals Nuclear Shuttling of She2p Couples ASH1 mRNA Localization to its Translational Repression by Recruiting Loc1p and Puf6p

2009 ◽  
Vol 20 (8) ◽  
pp. 2265-2275 ◽  
Author(s):  
Zhifa Shen ◽  
Nicolas Paquin ◽  
Amélie Forget ◽  
Pascal Chartrand
Keyword(s):  
Nuclear Import ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Mrna Localization ◽  
Translation Regulation ◽  
Importin Α ◽  
Localization Signal ◽  
Specific Proteins ◽  
Nuclear Shuttling ◽  
Ash1 Mrna

The transport and localization of mRNAs results in the asymmetric synthesis of specific proteins. In yeast, the nucleocytoplasmic shuttling protein She2 binds the ASH1 mRNA and targets it for localization at the bud tip by recruiting the She3p–Myo4p complex. Although the cytoplasmic role of She2p in mRNA localization is well characterized, its nuclear function is still unclear. Here, we show that She2p contains a nonclassical nuclear localization signal (NLS) that is essential for its nuclear import via the importin α Srp1p. Exclusion of She2p from the nucleus by mutagenesis of its NLS leads to defective ASH1 mRNA localization and Ash1p sorting. Interestingly, these phenotypes mimic knockouts of LOC1 and PUF6, which encode for nuclear RNA-binding proteins that bind the ASH1 mRNA and control its translation. We find that She2p interacts with both Loc1p and Puf6p and that excluding She2p from the nucleus decreases this interaction. Absence of nuclear She2p disrupts the binding of Loc1p and Puf6p to the ASH1 mRNA, suggesting that nuclear import of She2p is necessary to recruit both factors to the ASH1 transcript. This study reveals that a direct coupling between localization and translation regulation factors in the nucleus is required for proper cytoplasmic localization of mRNAs.

Abstract P351: The Post-transcriptional Regulations Of Centrosomal Plp Mrna In Drosophila

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Junnan Fang
Keyword(s):  
Translational Control ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Cell Types ◽  
Mrna Localization ◽  
Rna Localization ◽  
Embryonic Lethality ◽  
Cellular Processes ◽  
Pericentriolar Material ◽  
And Function

Centrosomes, functioning as microtubule organizing centers, are composed of a proteinaceous matrix of pericentriolar material (PCM) that surrounds a pair of centrioles. Drosophila Pericentrin (Pcnt)-like protein (PLP) is a key component of the centrosome that serves as a scaffold for PCM assembly. The disruption of plp in Drosophila results in embryonic lethality, while the deregulation of Pcnt in humans is associated with MOPD II and Trisomy 21.We recently found plp mRNA localizes to Drosophila embryonic centrosomes. While RNA is known to associate with centrosomes in diverse cell types, the elements required for plp mRNA localization to centrosomes remains completely unknown. Additionally, how plp translation is regulated to accommodate rapid cell divisions during early embryogenesis is unclear. RNA localization coupled with translational control is a conserved mechanism that functions in diverse cellular processes. Control of mRNA localization and translation is mediated by RNA-binding proteins (RBPs). We find PLP protein expression is specifically promoted by an RNA-binding protein, Orb, during embryogenesis; moreover, plp mRNA interacts with Orb. Importantly, we find overexpression of full-length PLP can rescue cell division defects and embryonic lethality caused by orb depletion. We aim to uncover the mechanisms underlying embryonic plp mRNA localization and function and how Orb regulates plp translation.

scholarly journals The structure of the Myo4p globular tail and its function in ASH1 mRNA localization

2010 ◽  
Vol 189 (3) ◽  
pp. 497-510 ◽  
Author(s):  
Alexander Heuck ◽  
Ingrid Fetka ◽  
Daniel N. Brewer ◽  
Daniela Hüls ◽  
Mary Munson ◽  
...  
Keyword(s):  
Mrna Localization ◽  
Surface Patch ◽  
X Ray ◽  
Membrane Tethering ◽  
Dividing Cells ◽  
Dependent Transport ◽  
Type V ◽  
Ash1 Mrna

Type V myosin (MyoV)–dependent transport of cargo is an essential process in eukaryotes. Studies on yeast and vertebrate MyoV showed that their globular tails mediate binding to the cargo complexes. In Saccharomyces cerevisiae, the MyoV motor Myo4p interacts with She3p to localize asymmetric synthesis of HO 1 (ASH1) mRNA into the bud of dividing cells. A recent study showed that localization of GFP-MS2–tethered ASH1 particles does not require the Myo4p globular tail, challenging the supposed role of this domain. We assessed ASH1 mRNA and Myo4p distribution more directly and found that their localization is impaired in cells expressing globular tail–lacking Myo4p. In vitro studies further show that the globular tail together with a more N-terminal linker region is required for efficient She3p binding. We also determined the x-ray structure of the Myo4p globular tail and identify a conserved surface patch important for She3p binding. The structure shows pronounced similarities to membrane-tethering complexes and indicates that Myo4p may not undergo auto-inhibition of its motor domain.

scholarly journals ASH1mRNA Anchoring Requires Reorganization of the Myo4p-She3p-She2p Transport Complex

2004 ◽  
Vol 279 (44) ◽  
pp. 46286-46294 ◽  
Author(s):  
Graydon B. Gonsalvez ◽  
Jaime L. Little ◽  
Roy M. Long
Keyword(s):  
Mrna Localization ◽  
Complex Model ◽  
Cell Nuclei ◽  
Daughter Cells ◽  
Complex Forms ◽  
Actin Cables ◽  
Type V ◽  
Localization Elements ◽  
Transport Complex

One mechanism by which cells post-transcriptionally regulate gene expression is via intercellular and intracellular sorting of mRNA. InSaccharomyces cerevisiae, the localization ofASH1mRNA to the distal tip of budding cells results in the asymmetric sorting of Ash1p to daughter cell nuclei. Efficient localization ofASH1mRNA depends upon the activity of fourcis-acting localization elements and also upon the activity oftrans-factors She2p, She3p, and Myo4p. She2p, She3p, and Myo4p have been proposed to form anASH1mRNA localization particle. She2p directly and specifically binds each of the fourASH1 cis-acting localization elements, whereas She3p has been hypothesized to function as an adaptor by recruiting the She2p-mRNA complex to Myo4p, a type V myosin. The Myo4p-She3p-She2p heterotrimeric protein complex has been proposed to localize mRNA to daughter cells using polarized actin cables. Here we demonstrate that whereas the predicted Myo4p-She3p-She2p heterotrimeric complex formsin vivo, it represents a relatively minor species compared with the Myo4p-She3p complex. Furthermore, contrary to a prediction of the heterotrimeric complex model forASH1mRNA localization,ASH1mRNA artificially tethered to She2p is not localized. Upon closer examination, we found that mRNA tightly associated with She2p is transported to daughter cells but is not properly anchored at the bud tip. These results are consistent with a model whereby anchoring ofASH1mRNA requires molecular remodeling of the Myo4p-She3p-She2p heterotrimeric complex, a process that is apparently altered when mRNA is artificially tethered to She2p.

scholarly journals An Exclusively Nuclear RNA-Binding Protein Affects Asymmetric Localization of ASH1 mRNA and Ash1p in Yeast

2001 ◽  
Vol 153 (2) ◽  
pp. 307-318 ◽  
Author(s):  
Roy M. Long ◽  
Wei Gu ◽  
Xiuhua Meng ◽  
Graydon Gonsalvez ◽  
Robert H. Singer ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Mrna Localization ◽  
Yeast Cells ◽  
Rna Structures ◽  
Nuclear Factors ◽  
Mother Cells ◽  
Ash1 Mrna

The localization of ASH1 mRNA to the distal tip of budding yeast cells is essential for the proper regulation of mating type switching in Saccharomyces cerevisiae. A localization element that is predominantly in the 3′-untranslated region (UTR) can direct this mRNA to the bud. Using this element in the three-hybrid in vivo RNA-binding assay, we identified a protein, Loc1p, that binds in vitro directly to the wild-type ASH1 3′-UTR RNA, but not to a mutant RNA incapable of localizing to the bud nor to several other mRNAs. LOC1 codes for a novel protein that recognizes double-stranded RNA structures and is required for efficient localization of ASH1 mRNA. Accordingly, Ash1p gets symmetrically distributed between daughter and mother cells in a loc1 strain. Surprisingly, Loc1p was found to be strictly nuclear, unlike other known RNA-binding proteins involved in mRNA localization which shuttle between the nucleus and the cytoplasm. We propose that efficient cytoplasmic ASH1 mRNA localization requires a previous interaction with specific nuclear factors.

scholarly journals A massively parallel reporter assay reveals focused and broadly encoded RNA localization signals in neurons

2021 ◽  
Author(s):  
Martin Mikl ◽  
Davide Eletto ◽  
Minkyoung Lee ◽  
Atefeh Lafzi ◽  
Farah Mhamedi ◽  
...  
Keyword(s):  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Neuronal Cell ◽  
Mrna Localization ◽  
Rna Localization ◽  
Massively Parallel ◽  
Reporter Assay ◽  
Massively Parallel Reporter Assay ◽  
Localization Behavior

AbstractAsymmetric subcellular localization of mRNA is a common cellular phenomenon that is thought to contribute to spatial gene regulation. In highly polar neurons, subcellular transcript localization and translation are thought to enhance cellular efficiency and timely responses to external cues. Although mRNA localization has been observed in many tissues and numerous examples of the functional importance of this process exist, we still lack a systematic understanding of how the transcript sorting machinery works in a sequence-specific manner.Here, we addressed these gaps by combining subcellular transcriptomics and rationally designed sequence libraries. We developed a massively parallel reporter assay (MPRA) for mRNA localization and tested ~50,000 sequences for their ability to drive RNA localization to neurites of neuronal cell lines. By scanning the 3’UTR of >300 genes we identified many previously unknown localization regions and mapped the localization potential of endogenous sequences. Our data suggest two ways the localization potential can be encoded in the 3’UTR: focused localization motifs and broadly encoded localization potential based on small contributions.We identified sequence motifs enriched in dendritically localized transcripts and tested the potential of these motifs to affect the localization behavior of an mRNA. This assay revealed sequence elements with the ability to bias localization towards neurite as well as soma. Depletion of RNA binding proteins predicted or experimentally shown to bind these motifs abolished the effect on localization, suggesting that these motifs act by recruiting specific RNA-binding proteins.Based on our dataset we developed machine learning models that accurately predict the localization behavior of novel sequences. Testing this predictor on native mRNA sequencing data showed good agreement between predicted and observed localization potential, suggesting that the rules uncovered by our MPRA also apply to the localization of native transcripts.Applying similar systematic high-throughput approaches to other cell types will open the door for a comparative perspective on RNA localization across tissues and reveal the commonalities and differences of this crucial regulatory mechanism.

scholarly journals Myo4p and She3p are required for cortical ER inheritance in Saccharomyces cerevisiae

2003 ◽  
Vol 163 (6) ◽  
pp. 1255-1266 ◽  
Author(s):  
Paula Estrada ◽  
Jiwon Kim ◽  
Jeff Coleman ◽  
Lee Walker ◽  
Brian Dunn ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Envelope ◽  
Actin Polymerization ◽  
Budding Yeast ◽  
Dynamic Network ◽  
Adaptor Protein ◽  
Mrna Transport ◽  
Yeast Saccharomyces Cerevisiae ◽  
Latrunculin A ◽  
Type V

Myo4p is a nonessential type V myosin required for the bud tip localization of ASH1 and IST2 mRNA. These mRNAs associate with Myo4p via the She2p and She3p proteins. She3p is an adaptor protein that links Myo4p to its cargo. She2p binds to ASH1 and IST2 mRNA, while She3p binds to both She2p and Myo4p. Here we show that Myo4p and She3p, but not She2p, are required for the inheritance of cortical ER in the budding yeast Saccharomyces cerevisiae. Consistent with this observation, we find that cortical ER inheritance is independent of mRNA transport. Cortical ER is a dynamic network that forms cytoplasmic tubular connections to the nuclear envelope. ER tubules failed to grow when actin polymerization was blocked with the drug latrunculin A (Lat-A). Additionally, a reduction in the number of cytoplasmic ER tubules was observed in Lat-A–treated and myo4Δ cells. Our results suggest that Myo4p and She3p facilitate the growth and orientation of ER tubules.

scholarly journals Multiple Myo4 motors enhance ASH1 mRNA transport in Saccharomyces cerevisiae

2010 ◽  
Vol 189 (4) ◽  
pp. 755-767 ◽  
Author(s):  
Sunglan Chung ◽  
Peter A. Takizawa
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Rna Binding ◽  
Purification Method ◽  
Class V ◽  
Transport Unit ◽  
Multiple Copies ◽  
Ash1 Mrna ◽  
Localization Element

In Saccharomyces cerevisiae, ASH1 mRNA is transported to the bud tip by the class V myosin Myo4. In vivo, Myo4 moves RNA in a rapid and continuous fashion, but in vitro Myo4 is a nonprocessive, monomeric motor that forms a complex with She3. To understand how nonprocessive motors generate continuous transport, we used a novel purification method to show that Myo4, She3, and the RNA-binding protein She2 are the sole major components of an active ribonucleoprotein transport unit. We demonstrate that a single localization element contains multiple copies of Myo4 and a tetramer of She2, which suggests that She2 may recruit multiple motors to an RNA. Furthermore, we show that increasing the number of Myo4–She3 molecules bound to ASH1 RNA in the absence of She2 increases the efficiency of RNA transport to the bud. Our data suggest that multiple, nonprocessive Myo4 motors can generate continuous transport of mRNA to the bud tip.

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